Liquid crystal display device

ABSTRACT

Provided is a liquid crystal display device, including: a plurality of scanning connection lines formed on at least one side of edges of the image display region, the plurality of scanning connection lines connecting together a scanning signal drive circuit and a plurality of scanning signal lines; a selection circuit formed so as to be interposed between the plurality of scanning connection lines and the plurality of scanning signal lines, the selection circuit being configured to selectively short-circuit one of a plurality of the scanning signal lines to one of the plurality of scanning connection lines based on a selection signal; and a selection signal line connected to the selection circuit, the selection signal line transmitting the selection signal to the selection circuit.

CROSS-REFERENCE TO RELATED APPLICATION

This application is Bypass Continuation of international patentapplication PCT/JP2013/001727, filed: Mar. 14, 2013 designating theUnited States of America, the entire disclosure of which is incorporatedherein by reference. Priority is claimed based on Japanese patentapplication JP2012-121406, filed: May 28, 2012. The entire disclosure ofJapanese patent application JP2012-121406 is incorporated herein byreference in its entirety.

TECHNICAL FIELD

This application relates to a liquid crystal display device.

BACKGROUND

In a general liquid crystal display device, a drive circuit is formedoutside an image display region that is a region in which a large numberof pixels are arranged to form an image to be displayed. The drivecircuit is configured to apply, to scanning signal lines connected togates of thin film transistors (TFTs) formed so as to correspond to therespective pixels, signals for controlling on and off of the TFTs. Forexample, in Japanese Patent Application Laid-open No. 2012-32608, thereis disclosed a liquid crystal display device in which drive circuitsformed of TFTs are arranged on both right and left sides of a displayregion.

In the liquid crystal display device, it is demanded to achieve higherresolution, which corresponds to increasing the number of pixels in theimage display region, and to achieve a narrower frame, which correspondsto reducing the size of a region outside the image display region.

In view of this, when the drive circuit for the scanning signal lines isformed in an outer region of the display device as in theabove-mentioned liquid crystal display device disclosed in JapanesePatent Application Laid-open No. 2012-32608, materials for forming thedrive circuit are limited, and hence the drive circuit cannot bedownsized beyond a certain limit. This becomes prominent when thematerials forming the drive circuit have relatively small electronmobility, such as amorphous silicon. Therefore, there is a limit onachieving a narrower frame in the configuration in which the drivecircuit for the scanning signal lines is formed in the outer region ofthe display device, and it is difficult to further reduce the framewidth in the related art.

On the other hand, when the scanning signal lines are individuallyconnected to an integrated circuit with use of wiring made of a materialhaving large electric conductivity, such as a metal, the number of thescanning signal lines to be connected is considerably increased in orderto achieve higher resolution in the image display region. A region forarranging such wiring increases in size, and hence it is still difficultto reduce the frame width in the related art.

This application has been made in view of the above-mentionedcircumferences, and has an object to achieve a narrower frame in theliquid crystal display device while maintaining the resolution.

SUMMARY

Embodiments disclosed in this application have various aspects, andrepresentative aspects among them may be summarized as follows.

(1) According to one embodiment of this application, there is provided aliquid crystal display device, including: an image display regionincluding a plurality of pixels sectioned by a plurality of scanningsignal lines and a plurality of video signal lines; a scanning signaldrive circuit formed on at least one side of edges of the image displayregion, which are parallel to the plurality of scanning signal lines; aplurality of scanning connection lines formed on at least one side ofedges of the image display region, which are parallel to the pluralityof video signal lines, the plurality of scanning connection linesconnecting together the scanning signal drive circuit and the pluralityof scanning signal lines; a selection circuit formed so as to beinterposed between the plurality of scanning connection lines and theplurality of scanning signal lines, the selection circuit beingconfigured to selectively short-circuit one of a plurality of thescanning signal lines to one of the plurality of scanning connectionlines based on a selection signal; and a plurality of selection signallines connected to the selection circuit, the plurality of selectionsignal lines transmitting the selection signal to the selection circuit.

(2) In the liquid crystal display device according to Item (1), theselection circuit is configured to connect one of the plurality ofscanning connection lines to a plurality of the scanning signal linesvia TFTs, the TFTs are formed for the plurality of the scanning signallines, respectively, and the plurality of selection signal lines areconnected to gate electrodes of the TFTs.

(3) In the liquid crystal display device according to Item (1) or (2),the selection circuit is formed between the image display region and theplurality of scanning connection lines so as to be parallel to theplurality of video signal lines.

(4) The liquid crystal display device according to any one of Items (1)to (3) further includes a selection canceling circuit formed on theother side of the edges of the image display region, which are parallelto the plurality of video signal lines, the selection canceling circuitbeing configured to selectively short-circuit corresponding one of theplurality of scanning signal lines to one of a plurality of selectioncanceling signal line based on the selection signal.

(5) In the liquid crystal display device according to Item (4), theselection canceling circuit is configured to connect the selectioncanceling signal line to the plurality of scanning signal lines viaTFTs, the TFTs are formed for the plurality of scanning signal lines,respectively, and the plurality of selection signal lines are connectedto gate electrodes of the TFTs.

(6) In the liquid crystal display device according to Item (4) or (5),the selection circuit and the selection canceling circuit are formed onone side of the edges of the image display region, which are parallel tothe plurality of video signal lines, the selection canceling circuit isformed on the other side of the edges of the image display region, whichare parallel to the plurality of video signal lines, at a positionopposing the selection circuit arranged on the one side, and theselection circuit is formed on the the other side of the edges of theimage display region, which are parallel to the plurality of videosignal lines, at a position opposing the selection canceling circuitarranged on the one side.

(7) In the liquid crystal display device according to Item (6), aplurality of the selection circuits and a plurality of the selectioncanceling circuits are alternatively formed on one side of the edges ofthe image display region, which are parallel to the plurality of videosignal lines, each of the plurality of the selection canceling circuitsis formed on the other side of the edges of the image display region,which are parallel to the plurality of video signal lines, at a positionopposing each of the plurality of the selection circuits arranged on theone side, and each of the plurality of the selection circuits is formedon the the other side of the edges of the image display region, whichare parallel to the plurality of video signal lines, at a positionopposing each of the plurality of the selection canceling circuitsarranged on the one side.

(8) In the liquid crystal display device according to any one of Items(4) to (7), the plurality of scanning signal lines are divided into ngroups, where n is a natural number of 2 or more, a number of theplurality of scanning connection lines is 1/n of a number of theplurality of scanning signal lines, the selection signal selects an m-thgroup of the n groups, the selection circuit is configured toshort-circuit corresponding one of the plurality of scanning connectionlines to corresponding one of the plurality of scanning signal lines,which belongs to the m-th group, and the selection canceling circuit isconfigured to short-circuit the selection canceling signal line tocorresponding one of the plurality of scanning signal lines, whichbelongs to the (m−1)th group. Note that, when m−1 is 0, the selectioncanceling circuit short-circuits the selection canceling signal line tocorresponding one of the plurality of scanning signal lines, whichbelongs to an n-th group.

(9) The liquid crystal display device according to any one of Items (1)to (8) further includes a sealing material for bonding an arraysubstrate and a color filter substrate to each other, the sealingmaterial being formed at a position overlapping with the plurality ofscanning connection lines and the selection circuit in plan view.

(10) In the liquid crystal display device according to any one of Items(1) to (9), a supply start timing to supply the selection signal to eachof the selection signal lines is earlier than a supply start timing tosupply a signal voltage corresponding to a pixel value via correspondingone of the plurality of video signal lines to corresponding one of theplurality of pixels, which corresponds to the each of the selectionsignal lines.

(11) The liquid crystal display device according to any one of Items (1)to (10) further includes an insulating film interposed between theselection circuit and the selection signal lines, in which the selectioncircuit and the selection signal lines overlap with each other in planview, and the selection circuit and the selection signal lines areconnected to each other via holes formed through the insulating film.

(12) In the liquid crystal display device according to any one of Items(1) to (11), a width of corresponding one of the plurality of scanningconnection lines, which is connected to corresponding one of theplurality of scanning signal lines located relatively farther from thescanning signal drive circuit, is larger than a width of correspondingone of the plurality of scanning connection lines, which is connected tocorresponding one of the plurality of scanning signal lines locatedrelatively closer to the scanning signal drive circuit.

(13) The liquid crystal display device according to any one of Items (1)to (12) further includes a reverse voltage application circuitconfigured to apply, to the selection circuit, a voltage having apolarity opposite to a polarity of the selection signal during anon-display period in which no image is displayed in the image displayregion.

(14) In the liquid crystal display device according to any one of Items(1) to (13), the selection circuit is configured to selectivelyshort-circuit one of a plurality of the scanning signal lines to each ofthe plurality of scanning connection lines during a selection period inwhich one of a plurality of the selection signal lines is selected bythe selection signal.

(15) In the liquid crystal display device according to Item (14), thescanning signal drive circuit is configured to sequentially output apulse signal to the each of the plurality of scanning connection linesduring the selection period in which one of the plurality of theselection signal lines is selected by the selection signal.

(16) In the liquid crystal display device according to Item (15), theplurality of scanning connection lines, the selection circuit, and theselection signal line are arranged on each of both sides of the edges ofthe image display region, which are parallel to the plurality of videosignal lines, and the plurality of scanning connection lines areconnected to both end portions of each of the plurality of scanningsignal lines.

(17) In the liquid crystal display device according to Item (16), theselection signal is alternately supplied to the selection circuitsarranged on the both sides of the edges of the image display region,which are parallel to the plurality of video signal lines.

(18) The liquid crystal display device according to Item (17) furtherincludes a reverse voltage application circuit configured to apply avoltage having a polarity opposite to a polarity of the selection signalto the selection circuit not supplied with the selection signal amongthe selection circuits arranged on both sides of the edges of the imagedisplay region, which are parallel to the plurality of video signallines.

According to the respective aspects of this application, a narrowerframe can be achieved while maintaining the resolution.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is an external perspective view of a liquid crystal displaydevice according to an embodiment of this application.

FIG. 1B is an external perspective view of a liquid crystal displaydevice according to another embodiment of this application.

FIG. 2 is a view illustrating configurations of circuits formed on anarray substrate of the liquid crystal display device according to anembodiment of this application.

FIG. 3 is a circuit diagram illustrating one pixel formed in an imagedisplay region.

FIG. 4 is a circuit diagram of a selection circuit and a selectioncanceling circuit of FIG. 2.

FIG. 5 is a time chart illustrating signals to be applied to scanningconnection lines and selection signal lines illustrated in FIG. 4.

FIG. 6 is an enlarged plan view of a part of the selection circuitformed on the array substrate and a peripheral portion thereof.

FIG. 7 is a partial sectional view of the liquid crystal display devicetaken along the line VII-VII of FIG. 6.

FIG. 8 is a partial sectional view of the liquid crystal display devicetaken along the line VIII-VIII of FIG. 6.

FIG. 9 is a partial sectional view of a liquid crystal display deviceaccording to a modified example in which the scanning connection linesare arranged more densely.

FIG. 10 is a partial sectional view of a liquid crystal display deviceaccording to another modified example in which the scanning connectionlines are arranged more densely.

FIG. 11 is a view illustrating configurations of circuits formed on anarray substrate of a liquid crystal display device according to anotherembodiment of this application.

FIG. 12 is a circuit diagram of selection circuits and selectioncanceling circuits of FIG. 11.

FIG. 13 is a time chart illustrating signals to be applied to thescanning connection line and the selection signal lines illustrated inFIG. 12.

FIG. 14 is a plan view schematically illustrating a part of theselection circuit formed on the array substrate and a peripheral portionthereof.

FIG. 15 is an enlarged view of a main part of FIG. 14.

FIG. 16 is a partial sectional view of the liquid crystal display devicetaken along the line XVI-XVI of FIG. 15.

FIG. 17 is a view schematically illustrating a modified example of thescanning connection lines.

FIG. 18 is a view illustrating a timing to apply a reverse voltage.

FIG. 19 is a view illustrating configurations of circuits formed on anarray substrate of a liquid crystal display device according to anotherembodiment of this application.

FIG. 20 is a circuit diagram of selection circuits illustrated in FIG.19.

FIG. 21 is a time chart illustrating signals to be applied to scanningconnection lines and selection signal lines illustrated in FIGS. 19 and20.

FIG. 22 is a time chart illustrating an operation timing of theselection circuits illustrated in FIGS. 19 and 20.

FIG. 23 is a plan view schematically illustrating a part of theselection circuit formed on the array substrate and a peripheral portionthereof.

FIG. 24 is a partial sectional view of the liquid crystal display devicetaken along the line XXIV-XXIV of FIG. 23.

FIG. 25 is a partial sectional view of the liquid crystal display devicetaken along the line XXV-XXV of FIG. 23.

DETAILED DESCRIPTION

Now, embodiments of this application are described with reference to thedrawings.

FIG. 1A is an external perspective view of a liquid crystal displaydevice 1 according to an embodiment of this application. The liquidcrystal display device 1 has a structure in which a liquid crystalmaterial with a thickness of about several micrometers is sandwichedbetween an array substrate 2 and a color filter substrate 3. A sealingmaterial formed along an outer periphery of the color filter substrate 3bonds the color filter substrate 3 to the array substrate 2 so as toseal the liquid crystal material without leakage.

The array substrate 2 is a glass substrate including, on a front surfacethereof, a large number of switching elements and pixel electrodesformed in matrix. When TFTs are used as the switching elements, thearray substrate 2 is also called a TFT substrate. The array substrate 2has a larger outer shape than that of the color filter substrate 3 asillustrated in FIG. 1A, and at least one side of the array substrate 2is extended out with respect to the color filter substrate 3 so that thefront surface thereof is exposed. On the exposed part of the frontsurface of the array substrate 2, a driver IC 21 is mounted, which is acontrol circuit for controlling on and off of the large number ofswitching elements and video signals to be applied to the respectivepixel electrodes. In addition, on the exposed part, a connectionterminal 22 is formed so as to electrically connect the liquid crystaldisplay device 1 to an external apparatus via, for example, a flexibleprinted circuit (FPC) or the like.

The color filter substrate 3 is a glass substrate including thin filmscolored with red, green, and blue for respective pixels that serve asunits for the liquid crystal display device 1 to form an image. Thecolored thin films are formed at positions corresponding to the pixelelectrodes formed on the array substrate 2.

Further, polarizing films 4 are bonded to the back surface of the arraysubstrate 2 and the front surface of the color filter substrate 3.

Further, as illustrated in FIG. 1B, on the exposed part of the frontsurface of the array substrate 2, that is, on a part formed of aprotruded short side of the array substrate 2 in the illustratedexample, a driver IC including a scanning signal drive circuit 211 and adriver IC including a video signal drive circuit 212 may be individuallyformed. In the illustrated example, in the part formed of the protrudedshort side of the array substrate 2, the video signal drive circuit 212is formed at a center portion in a direction parallel to the short side,and the scanning signal drive circuits 211 are respectively formed atboth end portions in the direction parallel to the short side. Thescanning signal drive circuits 211 and the video signal drive circuit212 are collected to the part formed of the protruded short side of thearray substrate 2. Thus, the frame width of the long side of the arraysubstrate 2 can be narrowed.

Note that, in the embodiment described above, the liquid crystal displaydevice 1 is a so-called transmissive liquid crystal display device, andthe array substrate 2 and the color filter substrate 3 are transparentsubstrates made of glass or the like. When the liquid crystal displaydevice 1 is a reflective liquid crystal display device, the arraysubstrate 2 and the color filter substrate 3 do not need to betransparent, and materials therefor are not limited to glass. Further,in the embodiment described above, the liquid crystal display device 1is a full-color display device, and hence the color filter substrate 3includes the thin films colored with red, green, and blue. However, thecombination of the colors may differ. Further, the liquid crystaldisplay device 1 may be a monochrome display device in which a thin filmcolored with a single color is used or the colored thin film is omitted.

FIG. 2 is a view illustrating configurations of circuits formed on thearray substrate 2 of the liquid crystal display device 1 according tothe embodiment of this application.

On the array substrate 2, a rectangular image display region 5 in whicha large number of pixels are arranged in matrix is formed. Note that,the resolution and the horizontal and vertical lengths of the imagedisplay region 5 are determined depending on the application of theliquid crystal display device 1. The liquid crystal display device 1exemplified in this embodiment has a vertically long shape (thehorizontal length is smaller than the vertical length). This is becausethe liquid crystal display device 1 is assumed to be used as a displaydevice for a personal digital assistance such as a so-called smartphone.Depending on the application, the image display region 5 may have ahorizontally long shape (the horizontal length is larger than thevertical length), or a shape in which the horizontal length is the sameas the vertical length.

On the array substrate 2, a plurality of scanning signal lines X and aplurality of video signal lines Y are formed so as to cross the imagedisplay region 5. The scanning signal lines X and the video signal linesY are formed orthogonal to each other so as to section the image displayregion 5 in matrix. A region surrounded by two adjacent scanning signallines X and two adjacent video signal lines Y corresponds to one pixel.

FIG. 3 is a circuit diagram illustrating one pixel formed in the imagedisplay region 5. A region illustrated in FIG. 3, which is surrounded byscanning signal lines Xn and Xn+1 and video signal lines Yn and Yn+1,corresponds to one pixel. The pixel referred to here is driven by thevideo signal line Yn and the scanning signal line Xn. A TFT 51 is formedin each pixel. The TFT 51 is turned on based on a scanning signal inputfrom the scanning signal line Xn. The video signal line Yn applies avoltage (signal representing a grayscale value of each pixel) to a pixelelectrode 52 of the corresponding pixel via the TFT 51 in the on state.

Further, a common electrode 53 is formed so as to correspond to thepixel electrode 52 so that a capacitor is formed via a liquid crystallayer sandwiched and sealed between the array substrate 2 and the colorfilter substrate 3. The common electrode 53 is electrically connected toa common potential. Therefore, based on the voltage applied to the pixelelectrode 52, an electric field between the pixel electrode 52 and thecommon electrode 53 changes, to thereby change the alignment state ofliquid crystal in the liquid crystal layer. In this manner, apolarization state of a light beam that transmits through the imagedisplay region 5 is controlled. The transmittance of the light beam thattransmits through the liquid crystal display device 1 is determinedbased on the relationship between the polarization direction to becontrolled by the liquid crystal layer and the polarization directionsof the polarizing films 4 bonded to the array substrate 2 and the colorfilter substrate 3. Each pixel functions as an element for controllingthe light transmittance. Then, the light transmittance of each pixel iscontrolled based on input image data to display an image. Therefore, inthe liquid crystal display device 1, a region in which the pixels areformed corresponds to the image display region 5 in which an image isdisplayed.

Note that, the substrate on which the common electrode 53 is formeddiffers depending on the system for driving the liquid crystal. Forexample, in a case of a system called in-plane switching (IPS), thecommon electrode is formed on the array substrate 2. Further, forexample, in a case of a system called vertical alignment (VA) or twistednematic (TN), the common electrode is formed on the color filtersubstrate 3. Although the system for driving the liquid crystal is notparticularly limited in this application, the IPS system is employed inthis embodiment.

Referring back to FIG. 2, the driver IC21 including the scanning signaldrive circuit 211 and the video signal drive circuit 212 is formed on atleast one side of edges of the image display region 5, which areparallel to the scanning signal lines X, that is, on an upper side ofthe image display region in the illustrated example. The driver IC 21inputs, from an external apparatus, various signals such as a powersupply voltage, a ground voltage, a timing signal, and a video signal.Note that, in this embodiment, the common potential is, but not alwayslimited to, the ground potential.

The scanning signal drive circuit 211 is connected to the scanningsignal lines X by a plurality of scanning connection lines 61 via aselection circuit 6. Further, an appropriate number of selection signallines 62 are extended from the scanning signal drive circuit 211 to beconnected to the selection circuit 6. The scanning signal drive circuit211 sequentially selects each of the scanning connection lines 61 at thetiming based on the timing signal input from the external apparatus, andapplies, to the selected scanning connection line 61, a voltage(hereinafter referred to as “on-voltage”) for turning on the TFT 51 (seeFIG. 3). Further, the same applies to the case of the selection signallines 62. The scanning signal drive circuit 211 sequentially selectseach of the selection signal lines 62 at the timing based on the timingsignal input from the external apparatus, and applies the on-voltage tothe selected selection signal line 62. This on-voltage applied to theselection signal line 62 corresponds to a selection signal to bedescribed later. The selection circuit 6 sequentially applies theon-voltage to each of the scanning signal lines X based on theon-voltages applied to the scanning connection line 61 and the selectionsignal line 62. When a voltage is applied to the scanning signal line X,the TFTs 51 connected to the scanning signal line X are turned on.

Further, a selection canceling circuit 7 is connected to, similarly tothe selection circuit 6, the scanning signal lines X and the selectionsignal lines 62, and is also connected to a selection canceling signalline 71. The selection canceling signal line 71 is applied with avoltage (hereinafter referred to as “off-voltage”) for turning off theTFT 51 (see FIG. 3). The selection canceling circuit 7 applies theoff-voltage to the scanning signal lines X at the timing based on theselection signal input from the selection signal line 62, to therebyturn off the TFTs 51 connected to the scanning signal line X. Note that,in this embodiment, the potential of the off-voltage is the commonpotential (that is, the ground potential).

Further, the scanning connection lines 61 are formed on at least oneside (in this embodiment, both sides) of edges (in the illustratedexample, right and left edges) of the image display region 5, which areparallel to the video signal lines Y. In this case, each of the scanningconnection lines 61 is arranged so as to be once led out from thescanning signal drive circuit 211 to a region horizontally outside ofthe image display region 5, then pass an outer side of the right or leftedge of the image display region 5 in parallel to the video signal linesY, and then be connected to the selection circuit 6. The selectioncircuit 6 and the selection canceling circuit 7 are arranged between theimage display region 5 and the scanning connection lines 61 so as to beelongated in parallel to the video signal lines Y.

Further, the video signal drive circuit 212 is connected to the videosignal lines Y. The video signal drive circuit 212 applies, insynchronization with the selection of the scanning signal line X by thescanning signal drive circuit 211 and the selection circuit 6, a voltagecorresponding to a video signal representing a grayscale value of eachpixel to each of the TFTs 51 connected to the selected scanning signalline X.

In the above-mentioned configuration, the number of the scanning signallines X and the number of the video signal lines Y depend on theresolution of the image display region 5. In this embodiment, when theresolution of the image display region is what is called HD 720p, thereare 1,280 scanning signal lines X and 2,160 (720×3) video signal linesY. In contrast, the number of the scanning connection lines 61 issmaller than the number of the scanning signal lines X. In thisembodiment, there are 320 scanning connection lines 61, which correspondto ¼ of the number of the scanning signal lines X. Further, fourselection signal lines 62 are formed on each of the right and left sidesto provide a total of eight selection signal lines 62, and one selectioncanceling signal line 71 is formed on each of the right and left sidesto provide a total of two selection canceling signal lines 71.

Although the selection circuit 6 is described in detail later, themeaning of the selection circuit 6 is briefly described now. Theselection circuit 6 is interposed between the scanning connection lines61 and the scanning signal lines X so as to selectively short-circuit aplurality of scanning signal lines X to one scanning connection line 61based on the selection signal. In the case of this embodiment, onescanning connection line 61 is associated with four scanning signallines X, and the selection of one of those four scanning signal lines Xis determined depending on to which of those four selection signal lines62 the on-voltage is applied. In other words, the selection circuit 6 isconfigured to divide the scanning signal lines X into four groupsdepending on with which selection signal line 62 the scanning signalline X is associated, and short-circuit, based on the selection signalfor selecting any one of those groups, the scanning connection line 61to the scanning signal lines X belonging to the corresponding group.With this, as a result of division of the scanning signal lines X intofour groups, the number of the scanning connection lines 61 may be ¼ ofthe number of the scanning signal lines X.

Note that, the division number of the scanning signal lines X is notlimited to 4, and may be an arbitrary number. In general, if the mostreasonable configuration is given in a case where the scanning signallines X are divided into n (n is a natural number of 2 or more) groups,the number of the scanning connection lines 61 is 1/n of the number ofthe scanning signal lines X. Further, the number of the selection signallines 62 and the number of the selection canceling signal lines 71 aresmall. Therefore, the number of signal lines to be arranged in theregion horizontally outside of the image display region 5, that is, atotal number of the scanning connection lines 61, the selection signallines 62, and the selection canceling signal lines 71 is significantlyreduced. In view of this point, the width necessary for the regionhorizontally outside of the image display region 5 is particularlyreduced, and hence the liquid crystal display device 1 may achieve anarrower frame.

Further, in the example illustrated in FIG. 2, the selection circuit 6and the selection canceling circuit 7 are formed on each of both theright and left sides of the image display region 5 (that is, in an upperhalf region of the image display region 5 in FIG. 2, the selectioncircuit 6 is formed on the left side of the image display region 5, andthe selection canceling circuit 7 is formed on the right side thereof,while in a lower half region of the image display region 5 in FIG. 2,the selection circuit 6 is formed on the right side of the image displayregion 5, and the selection canceling circuit 7 is formed on the leftside thereof). The reason for this is to equalize the number of thescanning connection lines 61 to be connected to the selection circuit 6between the right and left sides. In this example, the number of thescanning connection lines formed on each of the right and left sides is160. This configuration is achieved to equalize the width between theright and left frames of the image display region 5. When it isunnecessary to equalize the width between the right and left frames, theselection circuits 6 may be formed only on the left side (or the rightside) of the image display region 5, and the selection cancelingcircuits 7 may be formed only on the opposite side thereto.

FIG. 4 is a circuit diagram of the selection circuit 6 and the selectioncanceling circuit 7 of FIG. 2. FIG. 4 illustrates a region correspondingto the upper half of the image display region 5 of FIG. 2. A regioncorresponding to the lower half of the image display region 5 only has amirror-reversed arrangement of the selection circuit 6 and the selectioncanceling circuit 7, and other configurations are the same as those ofthe region corresponding to the upper half. Therefore, the illustrationand description of the region corresponding to the lower half areomitted.

In the center part of FIG. 4, a part of the scanning signal lines Xcorresponding to the upper half of the image display region 5 isillustrated. In this embodiment, the number of the scanning signal linesX is 1,280, and hence the upper half includes 640 scanning signal linesX. In FIG. 4, the scanning signal lines X are numbered as X1 to X640 inthe order of scanning. Further, four selection signal lines 62 areconnected to each of the selection circuit 6 and the selection cancelingcircuit 7. The respective selection signal lines 62 are numbered as 62-1to 62-4. Further, the scanning connection lines 61 are connected to theselection circuit 6. The number of the scanning connection lines 61 is ¼of the number of the scanning signal lines X in this case, and hencethere are 160 scanning connection lines in FIG. 4, which are numbered as61-1 to 61-160. Finally, the selection canceling signal line 71 isconnected to the selection canceling circuit 7.

In the selection circuit 6, TFTs 63 are formed so as to correspond tothe respective scanning signal lines X1 to X640. In this case, referringto the scanning connection line 61-1, four scanning signal lines Xrepresented by X1 to X4 are connected via the respective TFTs 63 to thescanning connection line 61-1, and further, gates of the four TFTs 63are connected to the different selection signal lines 62-1 to 62-4,respectively. With this configuration, by applying the on-voltage to anyone of the selection signal lines 62-1 to 62-4, the scanning connectionline 61-1 is short-circuited to corresponding one of the scanning signallines X1 to X4. The correspondence relationship among the TFTs 63 andthe selection signal lines 62 is as follows. The TFT 63 connected to thescanning signal line X1 is connected to the selection signal line 62-1,the TFT 63 connected to the scanning signal line X2 is connected to theselection signal line 62-2, the TFT 63 connected to the scanning signalline X3 is connected to the selection signal line 62-3, and the TFT 63connected to the scanning signal line X4 is connected to the selectionsignal line 62-4. Then, the TFT 63 connected to the next scanning signalline X5 is connected to the selection signal line 62-1 again, and thesame is repeated thereafter. As a result, the scanning connection lines61-2 to 61-160 also have the same configuration, and as illustrated inFIG. 4, the scanning connection line 61-160 is connected to therespective scanning signal lines X637 to X640 via the four TFTs 63.

Also in the selection canceling circuit 7, similarly, TFTs 72 are formedso as to correspond to the respective scanning signal lines X1 to X640,and all of the scanning signal lines X are connected to the selectioncanceling signal line 71 via the TFTs 72. Gates of the TFTs 72 are eachconnected to corresponding one of the selection signal lines 62-1 to62-4. The correspondence relationship among the TFTs 72 and theselection signal lines 62 differs from that in the case of the selectioncircuit 6. The TFT 72 connected to the scanning signal line X1 isconnected to the selection signal line 62-2, the TFT 72 connected to thescanning signal line X2 is connected to the selection signal line 62-3,the TFT 72 connected to the scanning signal line X3 is connected to theselection signal line 62-4, the TFT 72 connected to the scanning signalline X4 is connected to the selection signal line 62-1, and the same isrepeated thereafter.

In the configuration described above, the scanning signal lines X1 toX640 are divided into four groups associated with the selection signallines 62-1 to 62-4 via the TFTs 63. Then, by inputting the selectionsignal to the selection signal line 62, that is, by applying theon-voltage to any one of the selection signal lines 62-1 to 62-4,corresponding one group is selected, and the scanning signal line Xbelonging to the group is connected to the scanning connection line 61.Further, arbitrary one of the scanning connection lines 61 is connectedto the scanning signal lines X respectively belonging to differentgroups via the respective TFTs 63.

FIG. 5 is a time chart illustrating signals to be applied to thescanning connection lines 61 and the selection signal lines 62illustrated in FIG. 4. FIG. 5 illustrates a ½ scanning period as aperiod for scanning the scanning signal lines X in the upper half of theimage display region 5.

Description is given referring also to FIG. 4. First, at time t0,on-voltages are applied to the scanning connection line 61-1 and theselection signal line 62-1, and other scanning connection lines 16 andselection signal lines 62 are set to the off-voltage. As a result, onthe selection circuit 6 side, the TFTs 63 connected to the scanningsignal lines X1, X5, . . . , X633, and X637 are turned on. Among them,however, the scanning signal line connected to the scanning connectionline 61-1 is only the scanning signal line X1, and hence the on-voltageis input to the scanning signal line X1, and the TFTs 51 (see FIG. 3) inthe pixels connected to the scanning signal line X1 are turned on. Atthis time, on the selection canceling circuit 7 side, the TFT 72connected to the scanning signal line X1 is turned off.

Subsequently, at time t1, the voltage applied to the scanning connectionline 61-1 is maintained to the on-voltage. The off-voltage is applied tothe selection signal line 62-1, and the on-voltage is applied to theselection signal line 62-2. As a result, the on-voltage is input to thescanning signal line X2. At this time, on the selection cancelingcircuit 7 side, the TFT 72 connected to the scanning signal line X1 isturned on, and hence the scanning signal line X1 is short-circuited tothe selection canceling signal line 71. The voltage of the selectioncanceling signal line is the off-voltage, and hence the TFTs 51 (seeFIG. 3) of the pixels connected to the scanning signal line X1 areturned off. Similarly, at time t2, the on-voltage is applied to theselection signal line 62-3, and at time t3, the on-voltage issequentially applied to the selection signal line 62-4. Thus, theon-voltage is sequentially applied to each of the scanning signal linesX3 and X4. Simultaneously, the scanning signal lines X2 and X3 aresequentially set to the off-voltage.

Further, at time t5, the off-voltage is applied to the scanningconnection line 61-1, the on-voltage is applied to the scanningconnection line 61-2, and the on-voltage is applied again to theselection signal line 62-1. With this, the on-voltage is applied to thescanning signal line X5, and the scanning signal line X4 is set to theoff-voltage. This operation is repeated similarly up to the scanningconnection line 61-160 so that the on-voltage is sequentially applied toeach of the scanning signal lines X1 to X640 for scanning.

The above-mentioned operation is employed when the scanning signal linesX are divided into four groups. If this operation is generalized todescribe a case where the scanning signal lines X are divided into ngroups, when a signal for selecting an m-th group is given as theselection signal, in the selection circuit 6, the scanning connectionline 61 is short-circuited to the scanning signal line X belonging tothe m-th group, and in selection canceling circuit 7, the selectioncanceling signal line 71 is short-circuited to the scanning signal lineX belonging to a (m−1) th group. Note that, when m is 1, m−1 becomes 0.In this case, the scanning signal line X belonging to the n-th group isselected.

FIG. 6 is an enlarged plan view of a part of the selection circuit 6formed on the array substrate 2 and a peripheral portion thereof. Therespective members illustrated in FIG. 6 are formed with use of a knownsemiconductor manufacturing process by laminating, on a surface of thearray substrate 2, a gate electrode 633, a gate insulating film 635, asemiconductor layer 634, a source electrode 631, a drain electrode 632,and the like, which are arranged so as to overlap with each other asappropriate. In FIG. 6, in order to clarify the positional relationshipthereamong, an outer shape is illustrated also in the overlapped part.

The part illustrated in FIG. 6 is an upper portion of the selectioncircuit 6 of FIG. 4, in which the scanning signal lines X1 to X5 arepartially illustrated. A left end part of each of the scanning signallines X1 to X5 is formed into a comb shape to form the drain electrode632 (or the gate electrode) of the TFT 63. Then, the source electrode631 (or the drain electrode) having a comb shape is arranged so as to bealternately combined with the drain electrode 632 (that is, in aninterleave shape). The gate electrode 633 is formed in a layer under aregion in which the source electrode 631 and the drain electrode 632 arearranged. Note that, the source electrode 631 and the drain electrode632 are each formed into a comb shape and arranged so as to bealternately combined with each other because the length of a part inwhich the source electrode 631 and the drain electrode 632 face eachother may be increased to reduce the resistance between both theelectrodes.

Further, the source electrodes 631 of the TFTs 63 connected to thescanning signal lines X1 to X4 are collected into one line to beconnected to the scanning connection line 61-1 via a through hole. Onthe other hand, the gate electrode 633 of the TFT 63 connected to thescanning signal line X1 is connected to the selection signal line 62-1via a through hole, and the gate electrodes 633 of the TFTs 63 connectedto the scanning signal lines X2 to X4 are individually connected to therespective selection signal lines 62-2 to 62-4 via the through holes.The structures of the scanning signal line X5 and subsequent scanningsignal lines are similar to the above except that the source electrode631 of the TFT 63 is sequentially connected to the scanning connectionline 61-2 or the scanning connection line subsequent thereto.

FIG. 7 is a partial sectional view of the liquid crystal display device1 taken along the line VII-VII of FIG. 6. On the front surface of thearray substrate 2, the selection signal lines 62, the scanningconnection lines 61, the gate electrode 633, the semiconductor layer634, and the source electrode 631 are arranged through intermediation ofinsulating layers as appropriate. Further, the insulating layer betweenthe gate electrode 633 and the semiconductor layer 634 is particularlycalled the gate insulating film 635. The sectional view of FIG. 7illustrates a state in which the scanning connection line 61-1 isconnected to the source electrode 631 via the through hole. Further, onthe front surface of the array substrate 2, a functional film 23 such asa protective insulating film, a planarization film, and an alignmentfilm is formed as appropriate. A liquid crystal layer 8 is held betweenthe functional film 23 and a functional film 31 formed on a back surfaceof the color filter substrate 3 arranged so as to oppose the arraysubstrate 2. Further, a sealing material 9 for sealing the liquidcrystal layer 8 and causing the array substrate 2 to adhere to the colorfilter substrate 3 is formed at a position overlapping with the scanningconnection lines 61 and the selection circuit 6 in plan view asillustrated in FIG. 7. With this structure, a narrower frame can beachieved while effectively utilizing the scanning connection lines 61and the selection circuit 6.

FIG. 8 is a partial sectional view of the liquid crystal display device1 taken along the line VIII-VIII of FIG. 6. The sectional view of FIG. 8illustrates a state in which the selection signal line 62-4 is connectedto the gate electrode 633 via the through hole.

By the way, in the embodiment illustrated in FIGS. 7 and 8, the scanningconnection lines 61 are formed in the same layer, and the adjacentscanning connection lines 61 are arranged at necessary intervals basedon the process rule. However, by forming the scanning connection lines61 in different layers, the scanning connection lines 61 can be arrangedmore densely without changing the process rule.

FIG. 9 is a partial sectional view of the liquid crystal display device1 according to a modified example in which the scanning connection lines61 are arranged more densely. FIG. 9 illustrates a cross section at thesame position as FIG. 7. In this modified example, the plurality ofscanning connection lines 61 are arranged in different layersalternately. In plan view, at a gap between the adjacent scanningconnection lines 61 in a certain layer (for example, the scanningconnection lines 61-1 and 61-3), the scanning connection line 61 inanother layer (in the exemplified case, the scanning connection line61-2) is arranged. With this structure, a narrower frame is achieved byeffectively using a limited region and arranging the scanning connectionlines 61 more densely.

FIG. 10 is a partial sectional view of the liquid crystal display device1 according to another modified example in which the scanning connectionlines 61 are arranged more densely. Also FIG. 10 illustrates a crosssection at the same position as FIG. 7. In this modified example, theplurality of scanning connection lines 61 are arranged in differentlayers alternately. In plan view, in order to overlap with the scanningconnection line 61 arranged in a certain layer (for example, thescanning connection line 61-1), the scanning connection line 61 arrangedin another layer (in the exemplified case, the scanning connection line61-2) is arranged. In this structure, a narrower frame is achieved byeffectively using a limited region and arranging the scanning connectionlines 61 more densely.

Note that, it is preferred that the scanning connection line 61 and theselection signal line 62 be made of a material having large electricconductivity so as to reduce the resistances thereof. In this embodimentand the modified examples thereof, a metal such as copper and aluminumis used for the scanning connection line 61 and the selection signalline 62. In this case, when the scanning connection lines 61 arearranged as in the modified example of FIG. 9, in a region in which thescanning connection lines 61 are arranged, a light beam from the arraysubstrate 2 side is blocked by the light-blocking scanning connectionlines 61 to inhibit light transmission to the color filter substrate 3side. In contrast, when the scanning connection lines 61 are arranged asin the modified example of FIG. 10, in the region in which the scanningconnection lines 61 are arranged, there is a gap between the adjacentscanning connection lines 61. Therefore, a part of the light beam fromthe array substrate 2 side is blocked by the light-blocking scanningconnection lines 61, but the remaining part of the light beam transmitsto the color filter substrate 3 side. With use of this fact, forexample, a photocurable resin such as an ultraviolet curable resin maybe used for the sealing material 9. By radiating an appropriate lightbeam such as ultraviolet rays from the array substrate 2 side, thesealing material 9 can be cured.

FIG. 11 is a view illustrating configurations of circuits formed on thearray substrate 2 of the liquid crystal display device 1 according toanother embodiment of this application. FIG. 12 is a circuit diagram ofthe selection circuit 6 and the selection canceling circuit 7 of FIG.11. FIG. 13 is a time chart illustrating signals to be applied to thescanning connection line 61 and the selection signal lines 62illustrated in FIG. 12.

As illustrated in FIGS. 11 and 12, in the liquid crystal display device1 according to this embodiment, on both sides of edges (in theillustrated example, right and left edges) of the image display region5, which are parallel to the video signal lines Y, the plurality ofselection circuits 6 and the plurality of selection canceling circuits 7are alternately arranged. The plurality of selection circuits 6 and theplurality of selection canceling circuits 7 are arranged so as to opposeeach other.

In this embodiment, 15 scanning connection lines 61 are formed on eachof the right and left sides, 65 selection signal lines 62 are formed oneach of the right and left sides, and one selection canceling signalline 71 is formed on each of the right and left sides. CK0 to CK64 ofthe selection signal lines 62 represent the order of the application ofthe on-voltage. Further, 64 TFTs 63 are arranged in each block of theselection circuit 6, and 64 scanning signal lines X are associated withone scanning connection line 61. Further, 64 TFTs 72 are arranged ineach block of the selection canceling circuit 7.

Note that, the number of the selection signal lines 62 is larger by 1than the number of the TFTs 63 included in each block of the selectioncircuit 6 (that is, the number of the scanning signal lines X associatedwith one scanning connection line 61) and the number of the TFTs 72included in each block of the selection canceling circuit 7 for thereason described below.

As illustrated in FIG. 12, in the selection circuit 6, the TFT 63connected to the scanning signal line X1 is connected to the selectionsignal line 62 represented by CK0, the TFT 63 connected to the scanningsignal line X2 is connected to the selection signal line 62 representedby CK1, the TFT 63 connected to the scanning signal line X3 is connectedto the selection signal line 62 represented by CK2, the TFT 63 connectedto the scanning signal line X62 is connected to the selection signalline 62 represented by CK61, the TFT 63 connected to the scanning signalline X63 is connected to the selection signal line 62 represented byCK62, and the TFT 63 connected to the scanning signal line X64 isconnected to the selection signal line 62 represented by CK63. Then, theTFT 63 connected to the next scanning signal line X65 is connected tothe selection signal line 62 represented by CK0 again, and the same isrepeated thereafter. That is, in the selection circuit 6, no TFT 63 isconnected to the selection signal line 62 represented by CK64.

On the other hand, in the selection canceling circuit 7, the TFT 72connected to the scanning signal line X1 is connected to the selectionsignal line 62 represented by CK2, the TFT 72 connected to the scanningsignal line X2 is connected to the selection signal line 62 representedby CK3, the TFT 72 connected to the scanning signal line X62 isconnected to the selection signal line 62 represented by CK63, the TFT72 connected to the scanning signal line X63 is connected to theselection signal line 62 represented by CK64, and the TFT 72 connectedto the scanning signal line X64 is connected to the selection signalline 62 represented by CK0. Then, the TFT 72 connected to the nextscanning signal line X65 is connected to the selection signal line 62represented by CK2 again, and the same is repeated thereafter. That is,in the selection canceling circuit 7, no TFT 72 is connected to theselection signal line 62 represented by CK1.

FIG. 13 is a time chart illustrating a relationship among the signal tobe applied to the scanning connection line 61, the signals to be appliedto the selection signal lines 62, and the signals to be applied to thevideo signal lines Y. The horizontal axis represents time, and thevertical axis represents voltage. FIG. 13 illustrates a period in whichthe on-voltage is applied to one scanning connection line 61, that is, aperiod in which all of the scanning signal lines X corresponding to onescanning connection line 61 are scanned.

In this embodiment, there are 65 selection signal lines 62, and theon-voltage is sequentially applied to each of the selection signal lines62 represented by CK0 to CK64. When a period in which the on-voltage isapplied to each of the selection signal lines 62 represented by CK0 toCK64 is 1H, a period in which the on-voltage is applied to the scanningconnection line 61 is 65H.

Further, the TFTs 51 (see FIG. 3) of the respective pixels connected tothe 64 scanning signal lines X corresponding to the scanning connectionline 61 are sequentially applied with voltages d1 to d64 correspondingto grayscale values via the video signal lines Y. A period in which eachof the voltages d1 to d64 is applied is 1H, and a total period in whichthe voltages d1 to d64 are applied is 64H.

The timing to start application of the on-voltage to the scanningconnection line 61 and the timing to start application of the on-voltageto the selection signal line 62 represented by CK0 are earlier by 1Hthan the timing to start application of the voltage d1 to the videosignal line Y. Therefore, the on-voltages to be applied to the selectionsignal lines 62 represented by CK1 to CK64 and the voltages d1 to d64 tobe applied to the video signal lines Y are arrayed so that the numbersthereof match with each other.

The scanning signal line X1 is described referring also to FIG. 12.First, when the on-voltage is applied to the selection signal line 62represented by CK0, in the selection circuit 6, the TFT 63 connected tothe scanning signal line X1 is turned on. As a result, the TFTs 51 (seeFIG. 3) in the pixels connected to the scanning signal line X1 areturned on. Next, while the on-voltage is applied to the selection signalline 62 represented by CK1, the voltage d1 is applied to the TFT 51 viathe video signal line Y. After that, when the on-voltage is applied tothe selection signal line 62 represented by CK2, in the selectioncanceling circuit 7, the TFT 72 connected to the scanning signal line X1is turned on. As a result, the scanning signal line X1 isshort-circuited to the selection canceling signal line 71.

The operation is similar in the scanning signal line X2 and scanningsignal lines subsequent thereto. The scanning signal line X2 isdescribed. First, when the on-voltage is applied to the selection signalline 62 represented by CK1, in the selection circuit 6, the TFT 63connected to the scanning signal line X2 is turned on. As a result, theTFTs 51 in the pixels connected to the scanning signal line X2 areturned on. Next, while the on-voltage is applied to the selection signalline 62 represented by CK2, the voltage d2 is applied to the TFT 51 viathe video signal line Y. After that, when the on-voltage is applied tothe selection signal line 62 represented by CK3, in the selectioncanceling circuit 7, the TFT 72 connected to the scanning signal line X2is turned on. As a result, the scanning signal line X2 isshort-circuited to the selection canceling signal line 71.

Further, the scanning signal line X64 is described. First, when theon-voltage is applied to the selection signal line 62 represented byCK63, in the selection circuit 6, the TFT 63 connected to the scanningsignal line X64 is turned on. As a result, the TFTs 51 in the pixelsconnected to the scanning signal line X64 are turned on. Next, while theon-voltage is applied to the selection signal line 62 represented byCK64, the voltage d64 is applied to the TFT 51 via the video signal lineY. After that, when the on-voltage is applied to the selection signalline 62 represented by CK0, in the selection canceling circuit 7, theTFT 72 connected to the scanning signal line X64 is turned on. As aresult, the scanning signal line X64 is short-circuited to the selectioncanceling signal line 71.

In general, the timing at which the TFT 63 connected to the scanningsignal line Xn is turned on in the selection circuit 6 and the TFT 51 inthe pixel connected to the scanning signal line Xn is turned on isearlier by 1H than the timing at which the voltage do is applied to theTFT 51 via the video signal line Y. That is, a period in which the TFT51 is turned on is 2H, which is twice of the period in theabove-mentioned embodiment illustrated in FIG. 4. With this, even whenthe period (1H) in which the on-voltage is applied to each of theselection signal lines 62 is reduced along with the increase inresolution of the image display region 5, it is possible to sufficientlysecure the pixel charging time period.

FIG. 14 is a plan view schematically illustrating a part of theselection circuit 6 formed on the array substrate 2 and a peripheralportion thereof. FIG. 15 is an enlarged view of a main part of FIG. 14.FIG. 16 is a partial sectional view taken along the line XVI-XVI of FIG.15. In FIG. 14, WF represents a frame region, and SL represents asealing region.

In this embodiment, the selection circuit 6 and the selection signallines 62 overlap with each other in plan view. Specifically, theplurality of selection signal lines 62 extending in a direction parallelto the video signal lines Y in the image display region 5 overlap withthe plurality of TFTs 63 arrayed in the same direction in plan view. Theselection signal line 62 is arranged above the TFT 63, and a protectivefilm 652 and an organic insulating film 654 are interposed between theselection signal line 62 and the TFT 63. Further, the selection signalline 62 is covered with a protective film 656.

The protective films 652 and 656 are each a transparent insulating filmmade of silicon nitride (SiN₄) or the like similarly to the gateinsulating film 635. The organic insulating film 654 is a transparentinsulating film made of an organic material such as an acrylic resin.The organic insulating film 654 has a larger thickness and smallerdielectric constant than the protective films 652 and 656 or the gateinsulating film 635. Therefore, it is possible to reduce the parasiticcapacitance between the selection signal line 62 and the sourceelectrode 631 of the TFT 63 and the parasitic capacitance between theselection signal line 62 and the drain electrode 632 of the TFT 63.

In each corresponding set, the selection signal line 62 and the TFT 63are connected to each other via a hole formed through the organicinsulating film 654 or the like. Specifically, a hole that reaches thegate electrode 633 of the TFT 63 at the bottom is formed through theorganic insulating film 654, the protective film 652, and the gateinsulating film 635, and the selection signal line 62 is connected tothe gate electrode 633 of the TFT 63 via a via conductor 623 formed inthe hole. Further, the semiconductor layer 634 of the TFT 63 is arrangedso as to avoid the via conductor 623 and the vicinity thereof.

As described above, the selection signal line 62 overlaps with the TFT63 in plan view. Thus, a further narrower frame can be achieved ascompared to the above-mentioned embodiment illustrated in FIG. 6.

FIG. 17 is a view schematically illustrating a modified example of thescanning connection lines 61. In this embodiment, the scanningconnection lines 61-1 to 61-15 are respectively connected to theplurality of selection circuits 6 located at positions different fromeach other in a direction parallel to the video signal lines Y in theimage display region 5. Therefore, there is a difference in wiringlength of each of the scanning connection lines 61-1 to 61-15 from thescanning signal drive circuit 211 to each of the selection circuits 6.When the wiring length differs in this way, the difference in resistanceof each of the scanning connection lines 61-1 to 61-15 increases, whichmay cause a difference in display characteristics between a part of theimage display region 5 relatively closer to the scanning signal drivecircuit 211 and a part thereof relatively farther from the scanningsignal drive circuit 211.

In view of this, in the modified example, the width of the scanningconnection line 61 connected to the scanning signal lines X that arerelatively farther from the scanning signal drive circuit 211 is largeras compared to the width of the scanning connection line 61 connected tothe scanning signal lines X that are relatively closer to the scanningsignal drive circuit 211. With this, the difference in resistance ofeach of the scanning connection lines 61-1 to 61-15 is reduced, tothereby enable equalization of the display characteristics.

Specifically, the widths of the scanning connection lines 61-1 to 61-15are gradually increased as the selection circuit 6 to be connected isplaced apart from the scanning signal drive circuit 211. That is, as thenumber increases from the scanning connection line 61-1 to be connectedto the selection circuit 6 closest to the scanning signal drive circuit211 to the scanning connection line 61-15 to be connected to theselection circuit 6 farthest from the scanning signal drive circuit 211,the widths of the scanning connection lines 61-1 to 61-15 are graduallyincreased. This application is not limited thereto, and the widths ofthe scanning connection lines 61-1 to 61-15 may be increased in astepped manner.

FIG. 18 is a view illustrating the timing to apply a reverse voltage. Inthe TFT 63 included in the selection circuit 6 and the TFT 72 includedin the selection canceling circuit 7, amorphous silicon is used, forexample. Those TFTs 63 and 72 are used with a relatively high frequencyas compared to the TFT 51 (see FIG. 3) in the pixel. Therefore, as theuse period of the liquid crystal display device 1 (display period fordisplaying an image in the image display region 5) accumulates,amorphous silicon in the TFTs 63 and 72 may deteriorate, which may causegradual increase in threshold voltages of the TFTs 63 and 72.

In view of this, in the scanning signal drive circuit 211 (example of areverse voltage application circuit) in this modified example, during anon-display period in which no image is displayed in the image displayregion, a voltage having a polarity opposite to that of the selectionsignal is applied to each of the gate electrodes of the TFTs 63 and 72.That is, when a positive on-voltage is applied via the selection signalline 62 to each of the gate electrodes of the TFTs 63 and 72 during thedisplay period, the scanning signal drive circuit 211 applies a negativevoltage to each of the gate electrodes of the TFTs 63 and 72 during thenon-display period. With this, it is possible to suppress increase ofthe threshold voltages of the TFTs 63 and 72 and to elongate the life ofthe liquid crystal display device 1.

Specifically, the reverse voltage is applied immediately before orimmediately after the display period during the non-display period. Thatis, before and after the display period, an activation sequence and astop sequence for activating and stopping the liquid crystal displaydevice 1 are executed, and hence at least one period of the activationsequence and the stop sequence is used to apply the reverse voltage.

For example, the reverse voltage is applied as follows. A negativevoltage (for example, −6 V) is applied to all of the selection signallines 62, and a positive voltage (for example, 18 V) is applied to allof the scanning connection lines 61, thereby applying a negative voltage(for example, −24 V) having an absolute value larger than that of theabove-mentioned on-voltage between the gate and the source of the TFT63. This state is maintained for about 0.1 to several seconds.

FIG. 19 is a view illustrating configurations of circuits formed on thearray substrate 2 of the liquid crystal display device 1 according toanother embodiment of this application. FIG. 20 is a circuit diagram ofthe selection circuit 6 illustrated in FIG. 19.

As illustrated in FIGS. 19 and 20, in the liquid crystal display device1 according to this embodiment, the plurality of selection circuits 6are arranged so as to oppose each other on both sides of edges (in theillustrated example, right and left edges) of the image display region5, which are parallel to the video signal lines Y. In this embodiment,unlike the above-mentioned embodiments, the plurality of scanningconnection lines 61 are led into the respective blocks of the selectioncircuits 6 in a branched manner to be connected via the TFTs 63 to thescanning signal lines X. Further, the TFTs 63 connected to thosescanning connection lines 61 are connected in common to one of theplurality of selection signal lines 62. Note that, in this embodiment,no selection canceling circuit 7 is provided.

In this embodiment, 30 scanning connection lines 61 are formed on eachof the right and left sides, and 64 selection signal lines 62 are formedon each of the right and left sides. Further, the selection circuits 6are formed as many as the selection signal lines 62, that is, 64selection circuits 6 are formed on each of the right and left sides. Thenumbers of VGL1 to VGL30 and VGR1 to VGR30 of the scanning connectionlines 61 represent the order of transmission of the pulse signal. Thenumbers of CKL1 to CKL64 and CKR1 to CKR64 of the selection signal lines62 represent the order of transmission of the selection signal.

The selection circuits 6 formed on the left side of the image displayregion 5 are described. The scanning connection lines 61 represented byVGL1 to VGL30 are led into the uppermost selection circuit 6 to beconnected to the scanning signal lines X1 to X30 via the TFTs 63connected to the selection signal line 62 represented by CKL1. Further,the scanning connection lines 61 represented by VGL1 to VGL30 are alsoled into the second selection circuit 6 to be connected to the scanningsignal lines X41 to X60 via the TFTs 63 connected to the selectionsignal line 62 represented by CKL2. The same is repeated up to the 64thselection circuit 6 thereafter.

Further, the same applies to the selection circuits 6 formed on theright side of the image display region 5. The scanning connection lines61 represented by VGR1 to VGR30 are led into the uppermost selectioncircuit 6 to be connected to the scanning signal lines X1 to X30 via theTFTs 63 connected to the selection signal line 62 represented by CKR1.Further, the scanning connection lines 61 represented by VGR1 to VGR30are also led into the second selection circuit 6 to be connected to thescanning signal lines X41 to X60 via the TFTs 63 connected to theselection signal line 62 represented by CKR2. The same is repeated up tothe 64th selection circuit 6 thereafter.

FIG. 21 is a time chart illustrating signals to be applied to thescanning connection lines 61 and the selection signal lines 62illustrated in FIGS. 19 and 20. FIG. 21 illustrates a case where theselection signal lines 62 (CKL1 to CKL64) and the scanning connectionlines 61 (VGL1 to VGL30) formed on the left side are used, but the sameapplies also to a case where the selection signal lines 62 (CKR1 toCKR64) and the scanning connection lines 61 (VGR1 to VGR30) formed onthe right side are used.

The scanning signal drive circuit 211 sequentially outputs, during aperiod in which the on-voltage is applied to one of the selection signallines 62 (CKL1 to CKL64), the pulse signal to each of the scanningconnection lines 61 (VGL1 to VGL30).

Specifically, the scanning signal drive circuit 211 sequentiallyoutputs, during a period in which the on-voltage is applied to theselection signal line 62 represented by CKL1 corresponding to theuppermost selection circuit 6, the pulse signal to each of the scanningconnection lines 61 represented by VGL1 to VGL30. With this, the pulsesignal is sequentially input to each of the scanning signal lines X1 toX30. Further, the scanning signal drive circuit 211 sequentiallyoutputs, during a period in which the on-voltage is applied to theselection signal line 62 represented by CKL2 corresponding to the secondselection circuit 6, the pulse signal to each of the scanning connectionlines 61 represented by VGL1 to VGL30. With this, the pulse signal issequentially input to each of the scanning signal lines X31 to X60. Thesame is repeated up to the 64th selection circuit 6 thereafter.

By the way, a voltage to be applied to the gate of the TFT containingamorphous silicon is generally relatively high. Also in the liquidcrystal display device 1 of this embodiment, the voltage to be appliedto the gate of the TFT 63 (for example, 28 V) is higher than the voltageof the pulse signal to be input to the scanning signal line X (forexample, 16 V). Therefore, as in this embodiment, by sequentiallyoutputting the pulse signal to each of the scanning connection lines 61during the period in which the on-voltage is applied to one of theselection signal lines 62, it is possible to reduce the frequency of theselection signal with a relatively-high on-voltage to be supplied to theselection signal line 62 as compared to other embodiments. As a result,in the liquid crystal display device 1 of this embodiment, it ispossible to suppress power consumption as compared to the otherembodiments.

Note that, when one scanning period in which one scanning signal line Xis scanned is represented by 1H, the pulse width (period) of the pulsesignal to be sequentially output to each of the scanning connectionlines 61 represented by VGL1 to VGL30 is set to 2H, and the period inwhich the on-voltage is applied to the scanning connection lines 61 isset to 31H. The reason for this setting is because, as illustrated inFIGS. 12 and 13, the timing at which the TFT 51 in the pixel connectedto the scanning signal line Xn is turned on is set earlier by 1H thanthe timing at which the voltage do is applied to the TFT 51 via thevideo signal line Y. With this, even when the one scanning period (1H)is reduced along with the increase in resolution of the image displayregion 5, it is possible to sufficiently secure the pixel charging timeperiod.

Referring back to FIGS. 19 and 20, in this embodiment, the left endportions of the scanning signal lines X are connected via the TFTs 63 tothe respective scanning connection lines 61 (VGL1 to VGL30) formed onthe left side, and the right end portions of the scanning signal lines Xare connected via the TFTs 63 to the scanning connection lines 61 (VGR1to VGR30) formed on the right side. Therefore, input of the pulse signalis possible from both of the right and left sides. Therefore, analternate usage mode is possible, such as using the selection circuits 6formed on one of both the right and left sides for input of the pulsesignal and resting the selection circuits 6 formed on the other side.

FIG. 22 is a time chart illustrating such an alternate usage mode. InFIG. 22, A represents a drive period, and R represents a resting period.In this embodiment, the side to be used for input of the pulse signal ofthe selection circuits 6 formed on both the right and left sides isswitched for every certain period T. In the resting period R, noselection signal is supplied, that is, no on-voltage is applied to theselection signal line 62 connected to the selection circuit 6 to berested. In addition, no pulse signal may be supplied to the scanningconnection line 61 connected to the selection circuit 6 to be rested.

Further, in FIG. 22, CS represents a reverse voltage application period.The reverse voltage application period CS is provided at a part ofpositions corresponding to the resting periods R (that is, positions atwhich the counterpart is the drive period A) instead of the restingperiod R. The frequency of the reverse voltage application period is setto, for example, about once in 1,000 times of the resting period R.Further, the switching period T is, for example, about 0.1 to severalseconds.

In the reverse voltage application period CS, as described above withreference to FIG. 18, a voltage having a polarity opposite to that ofthe selection signal is applied to the gate electrode of the TFT 63.That is, when a positive on-voltage is applied via the selection signalline 62 to the gate electrode of the TFT 63 in the drive period A, thescanning signal drive circuit 211 applies a negative voltage to the gateelectrode of the TFT 63 in the reverse voltage application period CS.With this, it is possible to suppress increase of the threshold voltageof the TFT 63 and to elongate the life of the liquid crystal displaydevice 1.

For example, in the reverse voltage application period CS, a negativevoltage (for example, −6 V) is applied to all of the selection signallines 62 to be rested, and a positive voltage (for example, 18 V) isapplied to all of the scanning connection lines 61, thereby applying anegative voltage (for example, −24 V) having an absolute value largerthan that of the above-mentioned on-voltage between the gate and thesource of the TFT 63.

The alternate usage mode for the selection circuits 6 formed on both ofthe right and left sides has been described above, but this applicationis not limited thereto. The selection circuits 6 formed on both of theright and lefts sides may all be used for input of the pulse signal. Inthis case, the TFT 63 included in the selection circuit 6 can bedownsized, and hence a narrower frame can be expected in the liquidcrystal display device 1. Note that, the selection circuits 6 may beformed on only one of the right and left sides.

FIG. 23 is a plan view schematically illustrating a part of theselection circuit 6 formed on the array substrate 2 and a peripheralportion thereof. FIG. 24 is a partial sectional view taken along theline XXIV-XXIV of FIG. 23. FIG. 25 is a partial sectional view takenalong the line XXV-XXV of FIG. 23. The basic configuration of theselection circuit 6 in this embodiment is similar to the above-mentionedconfiguration illustrated in FIGS. 6 to 8.

In this embodiment, a lower metal film (selection signal line 62, gateelectrode 633, scanning signal line X, and the like) arranged betweenthe array substrate 2 and the gate insulating film 635 and an uppermetal film (scanning connection line 61, source electrode 631, drainelectrode 632, and the like) arranged between the gate insulating film635 and the protective film 652 are connected to each other by aconnection conductor 639 formed on the protective film 652. Theconnection conductor 639 is connected to the lower metal film via a holepassing through the protective film 652 and the gate insulating film635, and is further connected to the upper metal film via a hole passingthrough the protective film 652. The connection conductor 639 is madeof, for example, indium tin oxide (ITO).

Further, the scanning connection line 61 and the source electrode 631arranged between the gate insulating film 635 and the protective film652 are connected to each other via bypass wiring 638 arranged betweenthe array substrate 2 and the gate insulating film 635 and via theconnection conductors 639 provided at both end portions of the bypasswiring 638.

By the way, the configurations arranged outside the image display region5, such as the selection circuit 6, the scanning connection line 61, andthe selection signal line 62, are formed together with theconfigurations arranged inside the image display region 5 during themanufacturing process of the array substrate 2. For example, the TFT 63of the selection circuit 6 is formed together with the TFT 51 (see FIG.3) of the image display region 5. Further, the connection conductor 639is formed together with the pixel electrode or the common electrodeformed in the pixel of the image display region 5.

As described above, with the connection conductor 639 formed togetherwith the pixel electrode or the common electrode and arranged on theprotective film 652, the lower metal film and the upper metal film areconnected to each other. In this manner, the connection conductor 639can be formed without adding a new step to the manufacturing process ofthe array substrate 2. That is, when the lower metal film and the uppermetal film are connected to each other by passing only through the gateinsulating film 635, it is necessary to add a step of forming a holethrough the gate insulating film 635 after the gate insulating film 635is formed before the protective film 652 is formed, but by forming theconnection conductor 639 together with the pixel electrode or the commonelectrode as in this embodiment, it is unnecessary to add a new step.

While the foregoing has described what are considered to be the bestmode and/or other examples, it is understood that various modificationsmay be made therein and that the subject matter disclosed herein may beimplemented in various forms and examples, and that they may be appliedin numerous applications, only some of which have been described herein.It is intended by the following claims to claim any and allmodifications and variations that fall within the true scope of thepresent teachings.

What is claimed is:
 1. A liquid display device, comprising: an imagedisplay region comprising a plurality of pixels defined by a pluralityof scanning signal lines and a plurality of video signal lines; aplurality of blocks, each of which includes a plurality of selectionTFTs formed outside the image display region, each selection TFT havinga gate electrode, a source electrode, and a drain electrode connected toone end of a corresponding one of the plurality of scanning signallines, each of the selection TFTs in one of the blocks having acorresponding selection TFT in the other blocks; a plurality of scanningconnection lines formed outside the image display region, each scanningconnection line connected to all source electrodes of the plurality ofselection TFTs included in a corresponding one of the plurality ofblocks; a plurality of selection signal lines, each of which isconnected to the gate electrodes of one set of the correspondingselection TFTs in the plurality of blocks, the corresponding selectionTFTs that are connected to one of the plurality of selection signallines being different from the corresponding selection TFTs that areconnected to the other of the plurality of selection signal lines; ascanning signal drive circuit providing selection signals to theplurality of selection signal lines, respectively, and applyingon-voltages to the plurality of scanning connection lines, respectively;and a plurality of canceling TFTs formed outside the image displayregion, each of the plurality of canceling TFTs having a first electrodeconnected to the other end of a corresponding one of the plurality ofscanning signal lines, and a second electrode connected to a selectioncanceling signal line to which off-voltage is applied, wherein each ofthe plurality of canceling TFTs is configured to selectivelyshort-circuit corresponding one of the plurality of scanning signallines to the selection canceling signal line based on the selectionsignal.
 2. The liquid crystal display device according to claim 1,wherein each of the plurality of canceling TFTs has a gate electrodeconnected to a corresponding one of the plurality of selection signallines.
 3. The liquid crystal display device according to claim 2,wherein a selection signal line which is connected to a canceling TFT isdifferent from a selection signal line which is connected to a selectionTFT connected to a scanning signal line connected to the canceling TFT.4. The liquid crystal display device according to claim 1, wherein theplurality of selection TFTs are formed on a side of one of the edges ofthe image display region that are parallel to the plurality of videosignal lines, and the plurality of canceling TFTs are formed on a sideof the other of the edges of the image display region that are parallelto the plurality of video signal lines.
 5. The liquid crystal displaydevice according to claim 1, wherein some of the plurality of selectionTFTs are formed on a side of one of the edges of the image displayregion that are parallel to the plurality of video signal lines, some ofthe plurality of canceling TFTs are formed on a side of the other of theedges of the image display region that are parallel to the plurality ofvideo signal lines, the rest of the plurality of selection TFTs areformed on the side of the other of the edges, and the rest of theplurality of canceling TFTs are formed on the side of the one of theedges.
 6. The liquid crystal display device according to claim 1,further comprising a sealing material for bonding an array substrate anda color filter substrate to each other, the sealing material beingformed at a position overlapping with the plurality of scanningconnection lines in plan view.
 7. The liquid crystal display deviceaccording to claim 1, wherein a supply start timing to supply theselection signal to a first selection signal line is earlier than asupply start timing to supply signal voltages corresponding to pixelvalues via the plurality of video signal lines to pixels correspondingto the first selection signal line.
 8. The display device according toclaim 1, comprising a reverse voltage application circuit configured toapply, to the gate electrodes of one set of the corresponding selectionTFTs via the corresponding one of the plurality of selection signallines, a voltage having a polarity opposite to a polarity of theselection signal during a non-display period during which no image isdisplayed in the image display region.